Electric switch



Dec. 28, 1937.v

G. A. JOHNSON ELECTRIC SWITCH Original Filed Dec. l5, 1933 MN5/V705'. 10M/X60?, n

Patented Dec. 28, 1937 1 UNITED stares PATENT osi-Fics i Application December 15, 1933, SerialNo. 702-,516 Renewedl September 10, 1936 ,254 Claims.

emplied herein an electrolier switch of the` character commonly known as a link switch used in connection with an overheadlighting fixture. One of the important objects of Athe invention is theV provision of a switchv structure which is capable of embodiment in a small compact structurepermittingits useeither in a canopy which affords a limited space therefor or on a chain or other xture suspension means where a small device of unobstrusive appearance is especially desirable. Y f j Another object ofthe invention is the provision of a switch construction which is simple and eiiicient, i easily assembled without requiring the use'ofscrewsor rivets and which may bemounted in a suitablev casing adapted to hold the parts together in assembled and operative relation.y

.su Another'object of the invention is the production of a switch in which the 'enclosing casing-is so formed that it may be: detachably mounted within a link of a xture suspension chain in order to facilitate the insertion' in or the'removal from V the link when desired. 1 Y A further object Yof vthe invention is the pro- .vision of a-switch construction which permits the lead wiresto/be attachedto the switch terminals without opening the casing which encloses the switch. e Y

VAn additional object is the provision of simple means for holding the movable parts-of the switchvwhich means is adapted to be locked to the insulating body containing the switch by a simpleturning movement without requiring. other fastening means. Y

Another object of the invention is the provision, for returning the actuating member to initial position, of a spring capable of being compressed 4,0 `intolat form to` avoid restricting the up anddown play of the actuating member when rotated there- V `by permitting, the depth of the insulating bodyrto be reduced. Y f f f Y Various other objects of the inventionl will be jin part obviousv and. in part described hereinafter. My invention contemplates in its preferred form i aninsulating body enclosed ina suitable casing and having a recess in one face adapted toserve` asa switch chamber forcontaining a pair of fixed contacts, a rotatable contact member for closing and opening a circuit by bridging engagement with and disengagement from said fixed con- Y tacts, a Vrotary actuating member adapted to be operated by a pull chain or other vmeans for turning said movable contactand a spring for (Cl. 20G-64) returning said actuating member .to initial posi, tion.

One of the important features of the invention resides in the method of Y connecting the fixed contacts in the switch chamber to terminals' mounted in recesses formed in the insulating body on opposite sidesof said chamber and opening out the side of saidbody. The fixed contacts are provided with portions projectingy into ,shallowrecesses in the bottom faceof said body and the 1Q terminals have portions extending into said shallow recesses which are connected tosaid contacts. This conduces to a very efcient and compactfcon'- struction and by providing suitable terminal openings in the casing, lead wires may be easily con- Teile nected -to the terminals without opening the casing,

Another feature of the invention consists in 'providing7 for the purpose of holding the switch parts in operative relation, means which may be (20 mounted inthe insulating body in the assembling process and locked thereto by a mere turning movement without requiring any other fastening means. One form of this means comprises a bridge provided with a pin toserve as a shaftfor the movable switch parts, the ends of the bridge being formed to lock into the insulating body when turned through a short arc. For holdingr the bridge in locked position the spring is so .y connectedto the bridgeas to exert a constant ,30 locking pressure in addition to its function of returning the actuating member to initial operating position. The provision ofV means of this Vcharacter simpliiies the switch construction and the assembling of the parts and makes possible p35 a smaller and more compact structure. f

Another feature of the invention relates to the provisionrof a spring which when compressed as- Sumes a flat form thereby permitting full up and down movement of the actuating member as it is o rotated to turn the movablecontact from one position to another without making it necessary to increase the depth of the insulating body. For this purpose I employ a spiral cone-shaped spring interposed between the bridge and the actuating 45 member which offers no appreciable resistance to the upward movement of the latter since it may be 7 easily compressed into flat form lying in arsingle plane.

In the accompanying drawing in which is shown K50 for purposes of illustration an electrolier switcht made in accordance with the invention, Figure 1 is a view in perspective oi. the switch mounted in a link of a xture suspension chain;

' Fig.r 2 is a plan view on an enlarged scale of the 55 switch with the cover of the casing in which it is enclosed. removed to expose the switch construction;

Fig. 3 is a bottom plan view of the same with the bottom of the casing cut olf to expose the bottom face of the insulating body;

Fig. 4 is an exploded View in perspective of all the various parts of the switch;

Fig. 5 is an exploded view in perspective of the insulating body, fixed contacts, terminals, movable contact and actuating member;

Fig. 6 is a vertical cross sectional View on line 6-6 in Fig. 2, and

Fig. 7 is a View in perspective of a switch having a modified form of insulating body and terminals.

Referring to Vthedrawing showing my invention embodied in a link switch, I indicates an insulating body of oval form having a top face II and a bottom face i2. The top face is provided with a centrally located recess or switch chamber I3 and with a pair of terminal recesses I4 and I5 arranged one on each side of said central recess, but on opposite sides of the longitudinal axis of said body and opening out opposite Ysides of said insulating body. The insulating body I may be made of porcelain or any other suitable moldable insulating material.

In the floor of the recess i3 is formed a central annular boss I5 surrounded by an annular series of ratchet teeth l1 shown as numbering four. On two alternate and opposite teeth are mounted 'a pair of thin fixed contacts 2l and 22 which correspond in shape to the shape of said ratchet teeth and serve as iacings to said teeth. Each of said contacts on its inner edge is provided with a pair of depending prongs or lingers 23 which project downwardly through an opening or slot in the door of the recess for connection to a terminal. Each of the terminal recesses I4 and I5 opens out the bottom face of the insulating body and mounted in said recesses respectively through vsaid openings are two terminals 24 and 25, each bored and threaded for carrying a binding screw 25. Each terminal is provided with a base 2l arranged on one side and at right angles to it, which base is fitted in a shallow recess formed in the bottom face of the insulating body. On one 'side the base of each Vterminal is provided with a small projecting ringer 28 which extends in between the lingers ci a xed contact and is connected thereto by solder 2S or in any other suitable manner (Fig. 3). By thus fastening a terminal to each of said fixed contacts, these members are locked in the insulating body in theirv respective positions.

Within the switch recess i3 are mounted the switch operating parts comprising a rotatable metallic contact member S2 adapted to bridge the iixed contacts for closing the circuit, an actuating member for rotating said member 52 to close and to open the circuit through said xed contacts and a spring 34 for returning the actuating member to initial position. For holding these parts in operative position a pin bridge is provided comprising a flat bar 35 having a depending pin 35 xed therein. The lower end of the pin ts within the annular boss I6 and the bar 35 is provided with downturned ends 3l having each a lateral open slot 38 which slots face in opposite directions in the two ends for engaging lugs 35 formed in recesses 4Q in opposite side walls of the switch recess I3 adjacent the top face il of the insulating body. When the pin bridge is inserted in position with its ends 3l in the recesses 46 and is given a slight turn Vactuating member and fastened thereto.

clockwise the slotted ends engage the lugs 39 which locks the pin. bridge in position against vertical movement.

The metallic contact member 32 is provided with a central hole 42, permitting it to be rotatably mounted on the pin 35, and with a pair of inclined radial wings 43 for engaging flatwise the xed contacts 2| and 22 on the oor of the switch recess I3. The center portion of the contact member 32 normally rides on the annular top of the boss l5 lwith the depressed wings 43 in engagement with the ratchet teeth Il.

The actuating member 33, which is of insulating material, is in the form of a circular block having on one side an extension 45 and is provided with a central bore permitting it to be rotatably mounted on the pin 36 above the movable contact 32. The bottom face of the actuating member is recessed and provided with an annular series of ratchet teeth 4S adapted to engage a pair of ears 4l formed on the movable contact 32 for turning it in a clockwise direction when the actuating member is rotated (Figs. 4 and 5).

For holding the actuating member in constant engagement with the movablecontact yet permitting a limited vertical movement thereof as the contact moves upwardly on the inclined ratchet teeth, the spring 34 is mounted on the pin 36 between the actuating member and the bridge 35 and its two ends are fastened to those members.

The top face of the actuating member is provided with a circular recess within which is seated in a marginal groove '5I the base of the spring 34 and its base end is turned outwardly through a slot 52 in the oor and side of the The apex end of the spring is fastened to the bridge by turning that end around an ear 53 centrally located in one side of the bridge. rThe spring is under compression at all times and as thus mounted it exerts a pressure upon the bridge in such a direction as to force it into locking engagement with the lugs 39 in the insulating body and a pressure upon the insulating member to return it to initial position. Preferably, I employ a cone-shaped spiral spring for this purpose because it can be compressed into a flat form in the recessed top of the actuating member on the up ward movement of that member and therefore, it is not necessary to provide any additional head room in the switch chamber than that required for the vertical movement of the actuating member when rotated. In consequence, the switch lcan be made of less depth than would ordinarily be required if head room had to be provided for the spring.

For rotating the actuating member to turn the movable contact, the extension 45 of that member is provided with a through and through recess 55 and a slot 55 in one end opening out the bottom edge thereof and in the recess is inserted the end ball 5'I of a ball-link pull chain 58 with the link 59 lying in the slot 55. The pull chain extends around rthe periphery of the actuating member inl a guideway 60 partially encircling the switch chamber and actuating member and out through a nipple E! formed integral with the insulating body Ill on one side face thereof. Adjacent the slot 55, the periphery of the actuating member may be provided with a depression in which is seated the second end ball of the chain to cause it to hug the actuating member closely. Preferably, the bore 62 of the nipple opens out the top thereof so that the chain may arcanes l ybe ysimply dropped into the Ynipple when` the rpartsare. beingassembled. 'The nippleY is Vprolvided with an outerthread for receiving anut 64 to hold the chain therein andi the nut is proi V`ided with a Haring bell-shaped mouth to facililtate the movement'of' the chain in the operation of the switch.' Y Y For enclosing the insulating body and the parts carried thereby any suitable casing maybe f1/0 provided and one such is shown in the drawing,

comprising a casing and a cover 1I. The casing corresponds in shape to the insulating body to enclose the same and is provided with a f'frontopening 12 to enclosethebase of the 1:5 nipple and 'with oppositey openings 14 and 15 to Aexpose the terminal recesses I4fand I5 andthe terminals therein. Preferably, the insulating body is provided with a projecting lip 16 surrounding each terminal recess except on the top,

'20 vwhich lips extend` outwardly through said openings 14 and 15 in the casing a distance sufficient to insulate eiectively the terminals and binding screws in the recesses. The bottom and top facesof the insulating body are insulated from V26 the casing and cover by disks 18 and 1 9 respec- -tively made from any suitable sheet insulating material. The disk 19 which covers the top face of the insulating body has portions which extend outwardly over the terminal recessesI to insulatey 40 sureon that side of the'casing to disengage. the

llug 83 from the hole 84. The rim 80 of the cover is cutaway at 85 toaccommodate the nipple 6I and'rat B6y and 81 where theflips of` the terminalY recesses I4 and'IEV project'fromtheinsulating f-zbody and the top-of the coveris extended partially over'said recesses but not to the edgejot the insulating disk 19. For securing the switch in a link oi a Vfixtmre suspension chain,` the cover and the bottom face 550 of the casing may be provided each with a pair of parallel ridges which, when the casing and cover are made of metal, may be formed by stamping,each pair of ridges being separated a sufcient distance to embrace'oneV side Aoi. a link "'55 9|'4 of the suspension chain. TheY switch may be mounted therein'by inserting one end of it into the link and then Yswiyelling the switch around that end'and it maybe removed in the same manner.rv

"90 -In Figure 7 is shown an insulating bodyl 92 having modied end portionsand terminals perlmittingfthe'use of different means for insulating the terminals. The two-ends of the insulating body instead of being roundedare-formedY with i-'Illi transverse straight faces 98'thereby creating a space between each end of the-body and. the rounded end of the casing. .The two-terminals -93 are provided each with'a base similar in fo-rm to the base 21 of terminals 24 and 25 which is V10 `connected to a xed contact in the same manner but the terminals themselves are arranged perpendicular to the longitudinal axis ofthe in sulating body and are set in shallow recesses rformed in theends 98 ofthe insulating body,

'715 the-upper end of each terminali being Vturned overi-and'countersunk inlthe top'face offs'ai'd.

lbody. `Eacheterminal carriesy a bindingscrew 99 *for theattachment of lead wires 94 thereto.V

For insulating therterminals from thecasing 110., the insulating disk 18. -mounted between the 5 bottoms of the insulating body and casing-isprovided with upright end-portions.. of sufficient Width to enclose entirely the ends of the insulating body, terminals and binding screws and to insulate them from-the casing. Each ofthe ifo lupright portions 95. is provided with a small openingSI through whichan insulated lead wire -94` extends outwardly from said casing. In -Fi'gure '1, the lead' wiresI 94- are, for the sake of clearness, shown erect but in practice they are, f1-friV after'being conn'ectedto` the binding screwsV 99 -carried by the terminals, turned laterally out through theopenings 96. In all' respects other than the foregoing, theswitch illustrated in Figure 'lis of the same construction as thatshown '20 in the remaining figures ofl the drawing.

y In 'assembling the switch, the ixed contacts are rst mounted on-alternate ratchet teeth in theswitch chamber and the terminals are then ad-ustedin` the terminal'recesses land their Ybases 21- soldered to the fingers 23 of the contacts which locks these parts in the yinsulating body.` The movable contact-may then be placed in position on the annular boss I6 in the switch chamber and after the spring 34 has been 'con- "$0 nected to the actuating member 33 and bridge 35 andthe end ofthe pull chain 58 locked in the vextension 45, these partsV are mounted in the Vthe switch chamberithe pullchain is laid inthe guidevvay 5D andin-the'nipple 6I after wliichthe nut 64 is threaded on the nipple'. Y

` Iii-mounting the insulating body and assembled 515 'parts' in thevcasing, the `insulating disk 18 is placed in the bottom of thecasing, then the'insulating body and the disk'19 on the top face thereof and finally the cover is adjusted in position andlocked-'to the casing. The nut 64fisiiii0 then screwed up on theA nipple into tight engagement with th Casing and the assembnng Operav `tion-is completei Y It will nbe observed that this assemblingoperationf is comparatively'simplo and requiresY no G55 fasteningmeans'such asscrews and the like with the exception of soldering the terminals vto the fixed contacts. The switch parts areall held in operative position by the pin 'bridge which "is held locked by the spiralspring. `f j 5 y The operation .of my Yswitclfr is very, simple. The recess I3 is in Y'plan 'approximately in theA .formA of a quadrant of a Vcircle and the spring 34f.und`er tension` holds the actuating member 33 in such position that its extensionv 45 Inor- A65 mally engages an end wall of theY recess I3 (Fig. 2') which servesas a stop for theinitial position of said member.` When a pull is exerted uponV the pull chain, it rotates the actuating member through an arc of approximately ninety PTO Vdegreesand in this operation theratchet teeth onl the bottom face of the actuating member engage theopposite upstanding lugs von the movable'icontact and turn it throughlanarcioflap- -proximately ninety degreesythat'is, Vfrom one Z715 ratchet tooth to the next succeeding one. In this movement the spring is tightened thereby reducing the width of the various coils and permitting the spring to be compressed into a single plane as the actuating member is forced upwardly on its supporting pin by the upward movement of the movable contact in sliding engagement with the inclined ratchet teeth on the oor of the switch chamber. The movable contact is thus moved up the inclined faces either of the two opposite teeth or of opposite contacts as the case may be until it slides off and drops into the next succeeding pair of ratchet teeth. If the wings of the rotatable contact yare in engagement with the xed contacts when that member is rotated, the wings drop off the xed contacts on two sides simultaneously and in this movement break the circuit by a movement transversly of the xed contacts which reduces the arcing to a minimum because the arcs, instead of being lengthened as they would be by a separation in a longitudinal direction, are smothered by the insulating material underlying the xed contacts. After this rotation has been accomplished and the chain has been released, the spring which has been tightened by the turning causes the actuating member tov be returnedV to its initial position, the ratchet teeth formed on the bottom face of the actuating member then slide over the lugs on the rotatable contact without causing a reverse movement thereof since the wings are locked against the vertical portions of the teeth on the iioor of the switch chamber into which they have just dropped.

After the switch has been assembled in the casing, the lead wires may be attached to the terminals without opening the casing by merely 'unscrewing the binding screws carried by the terminals, winding the lead wires around the Shanks of said screws and then tightening up the screws to hold the lead wires. This is an important advantage because it eliminates openingthe casing in order to connect the lead wire to the terminals.

The assembling of the modiied form shown in Figure 7 is essentially the same as the foregoing. To obviate the necessity of opening the casing to attach lead wires to the terminals when the switch is being installed in a lighting system, short length lead wires 94 may be attached to the binding screws in the assembling of the switch and the ends of these projecting out the casing may be fastened tothe circuit wires. f

In mounting the switch in a link of a fixture suspension chain, one end of the switch is inserted in the link and then by a slight turning movement the remaining portion of the switch is pushed into place to bring the sides of the link in between the parallel ridges 90 on opposite faces of the casing and cover, the edges of these ,ridges being slightly rounded to facilitate this operation.

By a similar movement, the switch may be removed from the link. The ridges are sufficiently deep to hold the switch in the link Vagainst pulls exerted upon the pull chain.

Although I have shown the insulating body and switch parts as mounted in a metallic casing, it is to be 'understood that the casing may be made of any suitable material vsuch as molded insulating material and when made of this material the use of the insulating disk 18 may be eliminated.

It is to be understood that my invention is not to be limited to the particular form of switch herein shown and described since it may be embodied in various other forms all within the purview of the following claims.

What I claim is:

1. In an electric switch, an insulating body having a Arecess in one face to afford a switch chamber, a pair of xed contacts mounted in said recess in spaced relation, a bridge having its ends locked in opposite portions ofl the side wall of said recess, a pin carried by said bridge and having its lower end seated in the floor of said recess, a movable contact rotatably mounted on said pin, an actuating member for moving said movable lcontact into and out of bridging engagement with said fixed contacts to closeand to open a circuit therethrough, a springfor holding said actuating member normally in a retracted position and a pull chain for operating said actuating member against the tension of said spring.

2. In an electric switch, an insulating body havl,

rotatably mounted on said pin, a spring for holding said actuating member normally in a retracted position and a pull chain for operating said actuating member against the tension of said spring.

3. In an electric switch, the combination of an insulating body having a recess in one face to form a switch chamber, a pair of xed contacts mounted in said -chamber in spaced relation, a

bridge having its ends locked in opposite portions of the side wall. of said recess, a pin carried by said bridge and 'having its lower end seated in the cor of said recess, a movable contact rotatably mounted in said chamber,` an actuating member for rotating said movable contact into contacts to close and to open a circuit therethrough, a spring for holding said actuating member normally ina retracted position and a pull chain for operating said actuating member` against the tension of said spring to rotate said movable contact.

4.111 anelectric switch, thecombination of an insulating body recessed to form a switch chamber, a pair of fixed contacts 4in said chamber, a,

bridge having its endslocked in opposite portions of the side wall of said recess, a pin carried by said bridger andhaving its lower end -seated in the floor of said recess, a rotatable contact, a

rotatable actuating memberA having ratchet teeth..

for rotating said rotatable contact into and out of bridging engagement with said fixed'contacts, said rotatable contact and said actua-ting member being both mounted on said pin, a pull'chain for rotating said actuating member and a cone- :.45 Vand out of bridging engagement-with said fixed shaped spiral spring for returning said actuating Abridge vand having its lower end seated in the aicaess oor of saidfchamber, ai-pair of li'ixed contacts mounted in said chambena movable contact and a contact actuating member rotatably .mounted y.

6. In an electric switch, the ycombination oan; insulating body recessed in one face to form na switch chamber, a `bridge mounted transversely of said 4chamber and having its ends locked in opposite sidewalls of rsaid chamber when turned in one direction, said bridge unlocking when turned in the opposite direction, a pin carried by saidl bridge and having its lower endj seated in the floor of said chamber,V a pair of -iiXed contacts mounted in saidjchamber, .a movable con- .Y

' tact anda contact actuating member rotatably mounted on and movable longitudinally said pin, means foroperating said actuating member'and a.A spring vfor returning'saidactuating member to Vinitial position Vwhen saidoperatingkmeans is released, said spring having one end connected to said bridge landbeing under compression a-t all times to hold said bridge', in locked position in the oppositewdirection, a pin 'carriedV by' said `'bridge andrhavingits; lower endseated in the floor ofsaid chamber, arpair of n xedcontactsimounted 'in said chamber, 'arotatable contact, arotatable lnso actuating member of insulating material for rotating said rotatable Contact into and `out of bridging engagement with said fixed contacts,

,bothlsaid rotatablecontact and actuating member` beingf rotatablyA mounted onand movable longitudinally of saidpin, means for rotating said vactuating member through a predetermined uarc to turnsaid, rotatable contact from` one position to another and a spring to'return said actu- ;ating member to initial position and for holding vsaid bridge in lockedposition. Y Y

r8.5 In anelectric switch, the combinationv ofan Vinsulating body, a pull-,chainswitch structure ymounted'therein anda casing enclosing said insulating body, said casing being providedon op- ,posite faces with pairs of parallel Yridges for de- `,tachably fastening said device in a linkofa fixture suspension-chain, thevridges ofv each of said pairs being adapted for receivingY andk holding .between them in closeengagement one side portion of said link. Y r

9. rIn an electric switch, the combination of an insulating body, a pair of fixedcontacts mounted therein, a pull-chain-switch for opening and closing a circuit through said contacts, an` open top casing for enclosing said insulating body and a cover for closing said casing, the opposite outsidefaces'of said casingand said cover being provided with means for detachablysecuring said switch in a link of a fixture suspension chain, said means comprising a pair of parallelV 10.1In an electric switch, an insulating bodyV having a recess in one'face to form a switch chamber, a pair of fixed contacts mounted in said recess in spaced relation, a pin bridge mounted in said recess, a contact rotatably mounted in said recess; an actuating member for moving said-contact into and out of bridging engagement with said xed contacts to close and to open a circuit therethrough, said contact and said actuating member being lcoselymounted on the pin portion of said pin bridge, a spring for hold-l ing said actuating member normally in a retracted position, a pull chain for operating said actuating member against the tension ofk said spring anda casing enclosing said insulating body, said casing beingprovided with means for detachably iasteningit within a link of a fixture suspension chain.

411.In an electric switch, an insulating body having a` recess in one face to form a switch chamber, a pair of xed contacts mounted in said recess, a pin bridge mounted in said recess, a contact rotatably mounted in said recess, an actuating member for movingsaid contact into and out of bridgingyengagement with'said xed contacts to close and to open a circuit there-Y through, said contact memberand said actuating member being looselyV mounted on the pin portion of said pin bridge',a spring for holding said actuating member'normally in a retracted position, a pull cha-in for operating said actuating member against ythe tension of said spring and a casing enclosing said insulating body, said casing vhaving two opposite faces each provided with a pair` of spaced `parallel lridgesfor vdetachably fastening `saidfcasing within a linkvof a fixture suspension-chain.. v

l 12,'In anelectric switch, the combination of an insulating body recessed in one face-togform a switch chamber, the walls ofy said chamber having -a pair of opposite recessed lugs adjacent the top face `of said body, a bridge mounted transversely of said chamber and having notched ends interlocking with said lugs, a pin carried Vby said bridgeV and having its lowerA end seated in, the floor of said chamber, a pair of fixed contacts mounted in said chamber, a movable contact and `a contact actuating member rotatably mounted jon said pin, means for operating said actuating member and a spring for returning said actuating member to initial position.

V13. In an electric switch, the combination of an insulating bodyv recessedto form a switchV l chamber, a pair ofrxed contacts mounted in said chamber, a pin bridge mounted in said recess, a rotatable cont-act, a rotatable actuating member of insulating material for rotating said rotatable Contact into and out of bridging engagement with said fixed contacts, said rotatable contact and said actuating memberbeing mounted on the pin portionv of said lpin bridge, means for rotating Vsaid actuating member through a predetermined rarc. to turn said rotatable contact from one position to another and a spring toy A,said chamber, a rotatable contact, a rotatable actuating member of insulating material for rotating said rotatable contact into and out of bridging kvengagement with said fixed contacts,

Vsaidsactuating member having a recess in one face, means for rotating'said actuating member throughi'a, predetermined arc to turn said rotatable contact 'from one position to another and a cone-shaped. spiral spring to return 4said .actuating member to initial position, said spring having one end connected to said actuating member within the recess in its face and being adapted to be compressed within said recess when said actuating member is rotated to turn said rotatable contact.

15. In an electric switch, an insulating body having a recess in one face to form a switch chamber and a threaded nipple projecting from one side thereof and provided with an open pull chain passage leading from said switch chamber out through said nipple, a pair of fixed contacts mounted in said recess in spaced relation, a movable contact mounted in said recess, an actuating member for moving said movable contact into and out or bridging engagement with said xed contacts to close and to open a circuit therethrough, a spring for holding said actuating member normally in a retracted position, a pull chain laid in said passage for operating said actuating member against the tension of said spring and a nut threaded on said nipple for closing the said open passage to retain the pull chain therein.

16. In an electric switch, an actuating member of insulating material having top and bottom parallel faces and being of circular form having a circumferential extension on one side, said member being recessed in its top and bottom faces and said extension having a recess opening out one end of said extension through a slot for holding the end of a pull-chain locked therein, the ceiling of the recess in said bottom face of said member being provided with an annular series of ratchet teeth for rotating a movable-contact and the recess in said top face being provided for housing a spiral spring when compressed.

17. In an electric switch, an insulating bodyr recessed in its top face, a pin bridge mounted in said recess, the wall of said recess at opposite points adjacent said top face and the ends of said bridge interlocking when said bridge is turned in one direction, a movable contact and an actuating member loosely mounted on the pin portion of said pin bridge, a pull-chain for rotating said actuating member through a limited arc to turn said movable contact,` and a coneshaped spiral spring for returning said actue ating member to initial position when said pullchain is released, said spring being under tension at all times to hold said bridge in locked position.

18. In an electric switch, an insulating body recessed in its top face, a pin bridge mounted in said recess, the wall of said recess at opposite points adjacent said top face and the ends of said bridge interlocking when said bridge is turned in one direction, a movable contact and an actuating member loosely mounted on the pin portion of said pin bridge and freely movable longitudinally said pin portion, a pull-chain for rotating said actuating member through a limited arc to turn said movable contact, and a cone-shaped spiral spring,l fastened at one end to said actuating member and at its other end to said pin bridge, for returning said actuating member to initial position when said pull-chain is released and for holding said pin bridge in locked position.

19. In an electric switch, an insulating body recessed in its top face, a pin bridge mounted in said recess, the wall of said recess at opposite points adjacent said top face and the ends of said bridge interlocking when said bridge is turned in one direction, a movable contact and an actuating member loosely mounted on the pin portion of said pin bridge, a pull-chain for rotating said actuating member through a limited arc to turnsaid movable contact, and a cone-shaped spiral spring for returning said actuating member to initial position when said pull-chain is released and for holding said pin bridge in locked position, said actuating member being recessed in its top face for housing said spring to permit free movement of said member longitudinally said pin portion.

20. In an electric switch, a one-piece insulating body having a recess in one face forming a switch chamber and a threaded projecting nipple provided with an open pull chain passageleading from said switch chamber out said nipple, a switch mounted in said chamber, a pull chain laid in said passage for operating said switch and a nut threaded on said nipple for closing said passage in said nipple to retain the said pull chain therein.

2l. In an electric switch, the combination of an insulating body recessed to form a switch chamber, a pair of fixed contacts in said chamber, a pin shaft mounted in said chamber, a movable contact, anY actuating member for rotating said contact into and out of bridging engagement with said iixed contacts, said contact and said actuating member being loosely mounted on said pin shaft and movable longitudinally said shaft and said actuating member being recessed in its top face, a spiral spring for holding said actuating member in a normally retracted position and in engagement with said contact, said spring being cone-shaped permitting it'to be compressed into at form within the recess in said actuating member to allow free upward movement of said actuating member longitudinally said pin when it I is turned to operate said movable contact and a pull chain for operating said actuating member to turn said contact.

22. In an electric switch, the combination of an insulating body recessed to form a switch chamber, a pair of iixed contacts in said chamber, a pin shaft fixed in said chamber, a rotatable contact, an actuating member for rotating said contact into and out of bridging engagement with said iixed contacts, said contact and said actuating member being loosely mounted on said pin shaft and movable longitudinally said shaft and said actuating member being recessed in one face, a spiral spring for holding said actuating member in a normally retracted position and in engagement with said contact, said spring being cone-shaped permitting it when under extreme tension to be compressed into iiat form within the recess in said actuating member to allow free upward movement of said actuating member longitudinally said pin when it is turned to operate said movable contact and a pull chain for operating said actuating member to turn said contact in a step-by-step manner.

23. In an electric switch, the combination of an insulating body recessed to form a switch chamber, a pair of fixed contacts in said chamber, a pin .shaft mounted in said chamber, a rotatable contact, an actuating member for rotating said contact into and out of bridging engagement with saidV xed contacts, said. contact and said actuating member being loosely mounted on said pin shaft and movable longitudinally said shaft and said actuating member being recessed in its top face, a spiral spring for holding said actuating member in anormally retracted position and in engagement with said contact,` said spring being cone-shaped permitting it to be compressed into nat form within the recess in said actuating member to allow free upward movement of said actuthrough a passage, a pair of fixed contacts in said f chamber, a pin shaft mounted in said chamber, a rotatable contact, an actuating member for rotating said rotatable contact into and out of bridging engagement with said fixed contacts, said, actuating member comprising a main circular body portion having a side extension and said rotatable contact and said actuating member being rotatably mounted on said pinV shaft and movable longitudinally thereof, a pull chain fastened at one end to said extension and laid around and between the circular portion of said actuating member and the circular Wall of said recess and leading out said passage, and a helical spring for holding said actuating member normally in retracted position with said extension in engage- Y ment with an end Wall of said recess and for returning it to initial position after rotation by said pull chain.

25. In an electric switch, the combination of an insulating body provided with a recess opening out one side of said body through a passage, a pair of fixed contacts in said chamber, a pin shaft mounted in said chamber, a movable contact and an actuating member for rotating said movable contact in a step-by-step manner into and out of bridging engagement With saidv fixed contacts, said movable contact and said actuating member both being rotatably mounted on said pin shaft, said actuating member having a main portion of circular form with a side extension, a pull chain fastened at one end to said extension andfextending around and between the circular portion of said actuating member and a wall of said recess and leading out of said passage, said recess being formed Vto limit the rotation of said actuating member to an arc of approximately ninety degrees, and a helical spring for holding said actuating member in retracted position with said extension in engagement with an end Wall of said recess and for returning it to initial posi'- tion after rotation by said pull chain.

GUSTAF A. JOHNSON. 

